Ok, I basically see her as what sheenplank used to be. Farm most of the game, harassing and using your ult to gank well. Both champs had MS buffs and passives, and both are based around low CD physical damage shots. Sheenplank was annoying, not OP, and I see her as the same way. Yes, if fed she can pop off 1.2k crits (with runes) and 1 shot some squishies, but her escape is really lackluster, even with the ult. If a shen is chasing you, even if you tumble, chances are he will still land the taunt because most dashes go MUCH farther than her tumble, and please don't ever compare it to flash. It's not even close to being a blink. Basically, she is a modified sheenplank. Slightly better harass and ranged attacks, with no heal/cleanse or dot.
tl;dr She hits hard like sheenplank, but she dies in the same ways.